A base station of a network may communicate with multiple mobile devices to exchange voice, data, control messages and other types of signals. In some cases, a channel may be accessible by the network and possibly by devices of other networks. For instance, contention based access may be used, in which devices monitor the channel for idle periods before beginning a transmission in the channel. Scenarios may arise in which a device mistakenly determines that the channel is available. The device may cause interference if it transmits when the channel is not really available. Accordingly, there is a general need for devices and methods to address such challenges in these and other scenarios.